This is a Universal Clock Winding Key set. It is for Even or Odd numbered clocks. These are made of solid brass, and new in the package. The even sizes are: 2.75mm 7/64 in (2), 3.25mm 1/8 in (4), 3.75mm 0.14 in (6), 4.25mm 11/64 in (8), 4.75mm 3/16 in (10). The odd sizes are: 3mm 1/8 in (3), 3.5mm 9/64 in (5), 4mm 5/32 in (7), 4.5mm (9), and 5mm 13/64 in (11) I also have these in odd or even winders by themselves, not as a set. If you aren't sure what number you need, buy the set! Please note: If you have Model (whatever) clock, I do not know if these will fit! There are literally tens of thousands of models of clocks. Your best bet is to measure the shaft that sticks out, and see if it matches up with what is listed above. FREE SHIPPING FOR PEOPLE IN THE USA!